Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

“All along I thought I still had plenty of time,” says Laurent, 39, of Lyons, Colo., who works as a marketing vice president. “I’m healthy, active, don’t smoke, live in a great, low-stress part of the country, so I had no idea that simply waiting could possibly lead to difficulties in getting pregnant. I figured that 40 was too old for sure — with a higher risk of Down syndrome, et cetera — but I didn’t think that 36 could be too old as well.”

Like many women, Laurent had heard about Hollywood’s leading ladies such as Geena Davis and Jane Seymour, and other women, having kids well into their 40s and beyond, so she figured there was no hurry. But all the while, her biological clock was ticking away.

“I waited, but when the time came that my husband and I wanted to have kids, we were shocked to find out that we had to see a fertility specialist,” she says. “You think you’re safe in waiting, but myself and many of my friends who waited are now paying the price — emotionally and financially.”

Thanks to fertility drugs and intrauterine insemination, Laurent gave birth to her son, Conor, last summer, and she’s now trying for another child. But plenty of women who wait too long to take a “pregnant pause” from their careers — and all-around business as usual — aren’t so lucky.

Women have long been wrestling with how to balance work and family planning, and delaying having babies to build their careers or even those of their husbands. Statistics show that as more women have entered the workforce since the mid-1970s, the percentage of first births to women ages 30 and up have increased fourfold, according to the American Fertility Association (AFA), a patient and advocacy group. But fertility experts say there are some surprising other reasons why couples wait too long to try to start their families.

What's the rush?
Ironically, fertility treatments — their success and widespread availability over the last decade — seem to have lulled women like Laurent, and even their partners, into complacency. Many people know somebody who’s been on fertility drugs or undergone in vitro fertilization (IVF). Or they’ve heard about women having babies later in life, so they figure, what’s the rush?

Case in point:
Frieda Birnbaum
, the 60-year-old New Jersey woman who gave birth to twins in May. News reports discussed her use of IVF, notes Madsen, but nothing about the need for donor eggs or embryos, even though experts say it's highly unlikely that Birnbaum conceived with her own eggs.

“I think that people do misinterpret the stories they hear in the media and they think, ‘Oh, that woman just had a really good doctor,’” Madsen says.

What's more, Birnbaum went on NBC's “TODAY” show and said it was her “mission” to help other women — and even “empower” them to be able to have more choices about their fertility.

Problem is that women may not realize that these stories make the news because they're the exception, not the norm, says Dr. Marcelle Cedars, director of reproductive endocrinology at the University of California, San Francisco. And trying to have a baby this way can come at an enormous financial and emotional toll.

Just one round of IVF costs an average of $12,400 — generally not covered by insurance — and women may need several rounds to conceive, especially the older they get. Whereas 37 percent of IVF cycles with a woman's own eggs result in a live birth for women 35 and under, that figure drops to about 11 percent for women ages 41 and 42.IVF simply may never work for some older women.

Another factor that experts worry will fuel complacency is egg-freezing, one of the most recent fertility developments. It promises to let women bank their eggs for use years down the line. While the technology is encouraging, it's still in its infancy and offers no guarantees. Still, fertilityexperts say, more and more women are pursuing it in a trend that could lead to more broken dreams of a family.

“I worry that women will make unwise choices,” says Cedars. A couple who feels they have an insurance policy with frozen eggs may decide to put off having their families even longer, and then be in for a shock when those eggs aren't viable. Cedars says the process of freezing seems to make eggs “age” as much as five years, so couples may not buy as much time as they think.

Of course, complacency can be worsened by ignorance. Many women still don't know even the basic facts about their fertility, Madsen says, such as when their fertility declines and what they can do to help preserve it.

An international survey of 17,500 women released last year by the AFA found that most respondents mistakenly thought their fertility began to decline at age 40. The countries surveyed included the United States, England, Sweden, Uganda, Germany, Israel, the Netherlands, Argentina and Turkey.

While it's true that fertility takes a nosedive at 40, the decline actually begins in a woman's late 20s and accelerates throughout her 30s at a rate of 3 percent to 5 percent per year.By age 40, a woman has just a 5 percent chance of getting pregnant naturally in any given month.

Even women who should know better, sometimes don’t — or maybe they're in denial, thinking they'll be the one to beat the odds. Dr. Richard Scott, director of reproductive endocrinology at the University of Medicine and Dentistry of New Jersey, says he recently saw a 45-year-old woman with a graduate degree in biology who said she wanted to get pregnant with her own eggs. But chances of that happening are slim.

While it’s true that, thanks to fertility treatments, many women get pregnant today who wouldn’t have a decade ago, Scott says, there still is a lot of misunderstanding about just what medicine can do to fight back the hands of time when it comes to baby-making.

“Clearly there’s a big gap out there,” he says.

Can't stop the clock
Dr. Richard Paulson, chief of reproductive medicine and infertility at the University of Southern California in Los Angeles, sees the same thing. “I think there’s still a huge level of ignorance about the biological clock,” he says.

Doctors can cheat time a bit by coaxing reluctant egg and sperm together, he says, but they can’t force aging, deteriorating eggs to miraculously make babies — and there's no indication science will make that happen any time soon.

“Our ability to reverse that is no more likely than our ability to reverse aging,” he says, but that point often is lost on women who feel they’re a specimen of health and wonder why they can't get pregnant.

It’s true that measures such as maintaining a healthy weight, avoiding sexually transmitted diseases and not smoking all can help prevent fertility problems, notes Dr. Sandra Carson, a professor of obstetrics and gynecology at Brown University and director of reproductive medicine and infertility at Women and Infants Hospital of Rhode Island in Providence.

But being healthy isn’t enough to override the biological clock. Fit women in their mid to late 30s can be “incredulous” that they can’t get pregnant, Carson says. “Just because you’re healthy doesn’t necessarily mean that you’ll be fertile.”

Carson was involved with a campaign launched by the American Society for Reproductive Medicine in 2001 that aimed to educate women about the age-related decline in fertility. But that campaign didn’t sit well with a lot of women who felt that doctors, many of them older men, were trying to tell young women that they should trade in their careers for the mommy track — and stay home barefoot and pregnant.

Carson believes the campaign did help some to raise awareness about a woman’s biological clock but that many couples today still aren’t deciding to start their families sooner.

“I’m concerned that it just makes women worry more and not really change their decisions,” she says.

Couples in their late 20s and early 30s often are still career-focused and they may be waiting to buy a car or a house. Or, like Steve Houghtaling of Kalispell, Mont., they just want to enjoy some more child-free years.

"I became a father at age 39 only because I was having too much fun," he says.

It also was important, though, for Houghtaling, now 54, who works as a quality assurance specialist at a call center, to be able to provide well for his family. "I did want to better myself to be able to offer a good life for not only my wife but my children," he says. "I didn't want to scrape by like my parents did."

As was the case with Houghtaling, priorities with men and women who delay having children often shift to starting a family by the time they're in their late 30s, but by then it may be too late for some.

Madsen says she's hopeful that more couples — and companies — are learning about the biological limits on fertility. “I think there is more awareness today of the need for women to take the pregnant pause in their careers and have their kids,” she says.

But that doesn't necessarily make it any easier to break away from a successful career and jump into pregnancy and parenthood — and then try to juggle it all with an employer who may or may not be family-friendly. “A lot of women feel trapped,” Madsen says.

‘Sold a bill of goods’
Heather Duvall, 37, of Burnsville, Minn., waited to have kids not just because of her career, but because her husband was finishing business school. So when the couple felt the time was right, they started trying and Duvall conceived. But the happy news wasn't met so warmly by one of her managers. She recalls him saying: "Heather, why did you have to go and get pregnant on us?”

He knew she most likely wouldn't be maintaining her current hours — from early in the morning until late in the evening — as a financial analyst. One woman at the company did keep up the pace and her 3-year-old developed an imaginary mommy as a result.

“I thought, gosh, I don’t want my kids to have an imaginary mommy,” Duvall says. So after her son was born eight years ago, she went back to work part-time, working from home. But she always felt pulled in two directions, especially since her son developed cerebral palsy — likely from complications during her difficult childbirth — and needed medical attention. So she quit working altogether and volunteers on the board of her hospital and takes care of her family, which now includes two kids.

She doesn't think women today — who are often raised to get advanced degrees and pursue high-powered careers, and are then confronted with the pressure to have children in a relatively narrow span of time — have an easy time of things.

“I think my generation has been sold a bill of goods,” Duvall says. “We've been told that we can have a career and children and we can take our time doing it. Everyone who lives on my street, in a metropolitan suburb, has used some type of fertility assistance.”

Helen Farmer, a professor emeritus of counseling psychology at the University of Illinois at Urbana-Champaign who has studied women in the workplace, says there is a long way to go before many women find any kind of work/family balance.

“Here we are in 2007 and it’s the same problems we were addressing in the ‘80s,” she says, referring to women trying to do it all yet not getting a lot of support from companies or having access to quality, affordable childcare. “We made some progress in the ‘70s and now it's still stalled.”

Law firms, universities and other white-collar employers have started making things easier for valued workers — women and men — to take time off for kids, allowing employees to return after an extended leave and still accrue time toward tenure, promotions or retirement plans, for instance, Farmer says. But many other employers still don't view parents, especially mothers of young children, as an asset: “They think they're not going to get as much dedication,” she says.

Still searching for Mr. Right
Of course, for many women, timing a family isn't just about career paths and being educated about their fertility. There's also that little issue of finding Mr. Right.

Ideally, Kerri Wakefield, 31, an academic advisor at the University of Maryland, would like to have kids before she's 35. But she's single and about to embark on a Ph.D. program in education at the University of Michigan, which she hopes to finish when she's 36.

“I worry about an increased risk of birth defects but hope that if I keep myself healthy, I will have healthy babies even after 35,” she says.

And if she doesn't find that special someone in the next few years and have kids of her own, she's not going to stress too much about it.

“If I can't conceive, I will definitely adopt,” she says, even as a single woman in her 40s. “I’ve never been really attached to having kids that have my genes. If you have love to share, then who cares if it came out of your womb?”